Micah Zenko of the Council on Foreign Relations has a great piece demonstrating the emptiness of calls for more American "leadership" to solve all of our foreign policy problems. Someone in the Obama administration helped trigger this line of argument two years ago by saying, as intended praise, that Obama was "leading from behind," a stupid way of labeling coalition diplomacy.
Anyway, Zenko properly criticizes those pundits and politicians who talk as if other nations would quickly fall into line if the President just made a few more phone calls. The real world doesn't work like that. Interests and power matter much more than atmospherics.